Working with the FBI, police said they have been investigating the elaborate scheme involving drugs, guns and human trafficking since November.

Baltimore City firefighter Jamar Simmons, 29, with Truck 25 out of Roland Park, and Franklin Coit, 33, were arrested earlier this week. The pair faces prostitution, drug and weapon charges.

Officials said Simmons has been a firefighter with the department since 2002. He has been suspended from the department without pay during the investigation.

Police said the two men were operating an online prostitution ring from a space inside a warehouse at 208 S. Pulaski St. in southwest Baltimore.

Investigators said a cyber-tip led them to websites advertising prostitution and jobs for prostitutes. Detectives said an informant also told police that Simmons and Coit had "three to six girls working as prostitutes at any given time" either at the warehouse or at "various hotels in the Baltimore area."

Authorities said a warrant was served Monday for computers, guns, condoms, sexual aides and ledgers that showed the operation had been going on for quite some time.

"I don't have an exact figure on it. I haven't seen the ledgers, but in what's being described to me by the detectives, there were some logs and things that would suggest that this operation was definitely not in its infancy," said Anthony Guglielmi, with the Baltimore City Police.

According to court documents, both men faced similar prostitution charges in 2010, but Simmons received probation before judgment. The charges against Coit were dropped, but officials said he does have a conviction for robbery and assault in another case.

Fire officials said they're doing their own investigation.

"Pending the outcome of the case, a judicial system will determine what his status will be," Baltimore City Fire Department spokesman Kevin Cartwright said.

He explained why Simmons was still a member of the department after the previous prostitution charges were brought.

"The outcome of the case by the judicial system would have to be a guilty plea (for one of our members to be dismissed). If that's not the case, we don't get into probation before judgment. If he's guilty, then that's how we would proceed with our penalties and dispositions," Cartwright said.

Residents in the neighborhood said they knew of the alleged operation, and some said it was common to see fliers in the neighborhood advertising for prostitution.